package jianzhi

func mirrorTree(root *TreeNode) *TreeNode {
	if root == nil {
		return nil
	}

	return root
}

func helper27(root *TreeNode) {
	if root.Left == nil && root.Right == nil {
		return
	}

	if root.Left != nil {
		helper27(root.Left)
	}
	if root.Right != nil {
		helper27(root.Right)
	}
	root.Left, root.Right = root.Right, root.Left

}
